“We expected to need more time to be ready,” the company said in a statement offered up to TechCrunch this weekend, “but we are happy to offer our customers the lower pricing right away. Initial supplies of some replacement batteries may be limited.”

Earlier this week, Apple announced the temporary price cut for battery replacements of older iPhone models. The service is usually $79, but the discount will remain in place until December 2018.

In the note, titled “A Message to Our Customers,” Apple apologized for the situation and also said that a future iOS update will give users a better idea of how battery life is affecting the performance of their iPhone.